Spider center bar and stem assembly



April 23, 1968 F. A. FERRARO 3,378,921

SPIDER CENTER BAR AND STEM ASSEMBLY Fil ed March 9, 1967 2 Sheets-Sheet 1 INVENTOR FRANK A. FERRARO BY W, W!

April 23, 1968 FERRARQ 3,378,921

SPIDER CENTER BAR AND STEM AS SEM BLY Filed March 9. 1967 V 2 Sheets-Sheet 6 INVENTOR J FRANK A. FERRARO BY \I/M,JMMI fl mm f l w ATT'YS.

United States Patent Office 3,378,921 Patented Apr. 23, 1968 3,378,921 SPIDER (IENTER BAR AND STEM ASSEMBLY Frank A. Ferraro, Monroe, Conn, assignor to Eversharp, Inc, Milford, (learn, a corporation of Delaware Filed Mar. 9, 1967, Ser. No. 621,888 4 (Ilaims. (Cl. 30--60.5)

ABETRACT OF THE DKSCLOSURE Means for adjoining a safety razor spider stem and center bar which allows the spider stem and center bar to be formed of fiat stock, reducing materal requirements, and permitting employment of faster and less expensive manufacturing techniques.

This invention relates to improvements in safety razors in general and, more specifically, relates to a new and improved spider subassembly, including a spider stern and center bar with a novel means to join the same in experitious, accurate and mechanically rigid manner.

As evidenced by the number of patents in the safety razor art, this field has been the object of considerable research and development. Even though this has resulted in the art being highly developed, there remains ample room for improvement, particularly where such effort will bring a reduction in the cost of the safety razor, for it is generally conceded by those familiar with the field that, at best, only a small margin of profit is realized from the manufacture and sale of safety razors. Of necessity, safety razors are precision instruments and, as such, must be manufactured to rather close tolerances. It logically follows that manufacturing cost are oftentimes increased because of the accuracy requirements.

Safety razors of the double edge type having sectional caps are well known and, generally, include a spider assembly consisting of a spider stem and center bar having cross braces at opposite ends which mount sectional caps adapted for engagement with ends of a blade seat and which open and close in response to axial movement of the spider assembly relative to the blade seat. This particularl design is oftentimes referred to as the sectional cap or clam shell-type of safety razor and has enjoyed considerable commercial success.

In the past, the spider stem in double edge razors of the sectional cap type has usually been formed of round stock, threaded at one end and bifurcated at the other. A center bar is positioned in the bifurcated end, and the center bar and spider stem joined by riveting or the equivalent. Threading of the lower end of the stem is usually accomplished by an automotic screw machine process, while bifurcating of the opposite end is accomplished by milling or the equivalent. It is evident that these manufacturing steps, while necessary to obtain the required degree of accuracy, were undesirable because of the high cost of manufacturing the parts and the material required. Unfortunately, a satisfactory and less expensive method was not available in view of the accuracy demands, so the previous techniques have been continued up to the developrnent of the present invention.

The present invention is directed to a unique solution of the problem discussed above. A spider stern may be formed from flat stock, such as sheet stock, polygonal rod stock or the like, and is stamped to form a tongue means at one end and threads at the opposite end. The threads are finished through coining operation and, thus, the former more expensive technique of forming threads on an automatic screw machine is eliminated. The tongue means formed at the upper end of the stem is received in a vertical slot formed in the center bar. The center bar may also be formed by stamping from single ply sheet stock, however, center bars formed by stamping and progressive folding operations may also be used. Locating surfaces are provided adjacent the slot and co-operate with locating surfaces on the stem to limit the insertion of the tongue means, allowing the axis of the stem to intersect and lie in the plane of the center bar. After insertion, the tongue means is deformed to fasten the center bar and spider stem together, such deforming step being accomplished by a punching operation. The resulting subassembly of spider stem and center bar is thus accurately formed and is considerably cheaper than predecessor designs. Operationally speaking, the spider subassembly performs the opening-and-closing (blade clamping) function with the degree of accuracy required for good shaving comfort.

A greater appreciation of the salient features of the present invention can be had on consideration of the objects and attendants description of a preferred form of the invention.

It is an object of this invention to provide a new and improved spider stem.

It is a further object of this invention to provide a new and improved spider stem and center bar assembly having a novel means for joining the parts together.

It is a further object of this invention to provide a new and improved spider stem and center bar assembly which is economical to manufacture and assemble, and which requires less material than existing designs of equivalent quality.

Objects other than those specifically set forth will become apparent when reference is made to the following description and accompanying drawings wherein:

FIGURE 1 is an exploded perspective view of the center bar and spider stem of the present invention;

FIGURE 2 is an enlarged elevational view of the upper end of the spider stem shown in FIGURE 1;

FIGURE 3 is a front elevational view of the upper end of the spider stem shown in FIGURE 2;

FIGURE 4 is an enlarged elevational view of the center bar shown in FIGURE 1;

FIGURE 5 is a cross-sectional view taken generally along the line 55 of FIGURE 4;

FIGURE 6 is an end elevational view of the center bar with the stem shown fragmentarily with the laterally projecting tongues shown in dotted lines before deformation, and in solid lines in the position assumed after the punch (shown fragmentarily) has completed the deforming or expanding operation; and

FIGURE 7 is a cross-sectional view through the center bar at the slot, being taken along the side of the stem after joining to the center bar.

In FIGURE 1, a center bar 11 and] spider stem 15 are illustrated in exploded perspective disassembled relation and form a spider subassembly, indicated generally by reference numeral 10. The center bar 11 is provided with downwardly projecting arms 12 and 13 at opposite ends, which arms are adapted for loose positioning in slots formed in the blade seat of a safety razor in a manner well known. The particular shape of the arms 12 and 13 and the constructional features of the means at opposite ends of the arms for receiving cross braces which mount the sectional caps are shown in co-pending application Ser. No. 618,789, filed Feb. 27, 1967. Obviously, other forms of arms and center bars may be used in conjunction with the present invention. An attaching portion at the middle of the center bar is provided with a vertical slot 14 for reasons to become apparent.

A spider stem 15 may be formed from sheet or rod stock and has threads 16 formed at one end. The threads 16 may be of any suitable type which are easily formed by stamping and coining, such as a buttress type. At the upper end of the stem 15 is provided a pair of spaced laterally projecting tongues 17 and 18 which are adapted for insertion through the slot 14 to join the center bar 11 and stem 15 in a manner to be described in detail with particular reference to FIGURES 6 and 7.

As seen in FIGURES 2 and 3, the tongues 17 and 18 are formed by removing a generally rectangular portion of the material from the stem 15. The tongue 18 is provided with a lower wall 20 and an upper wall 21 of greater axial length, terminating in a vertical shoulder 22. The upper and lower walls 20 and 21 merge with an end margin 23 of the stem 15 through angularly directed or chamfered portions 24 and 25. The inner end of the lower wall 20 terminates at a vertical wall 26 which extends to an upper wall portion 27 formed on the lower tongue 17.

The lower tongue 17 is provided with chamfered portions 28 and 29 which merge with the vertical wall 30. The tongue 17 includes a lower wall portion 31, which terminates in a vertical wall 32, disposed parallel to the wall 26 and laterally offset relative to the wall 22. The vertical wall 32 may be disposed along the center line or axis of the stem 15 and terminates at a lower wall 33, extending outwardly through a chamfer 34 to the side of the stem 15.

As seen in FIGURE 4, the slot 14 is bounded by wall portions 40, 41, 42 and 43. The wall portions 40, 41 and 43 are of uniform thickness, this being equal to the thickness of the stock from which the center bar 11 is formed. The lower wall portion 42 is of reduced thickness, as is apparent in the cross-sectional views of FIG- URES 5 and 7. A part of the center bar face 45 is coined to form a recessed vertical surface 44 intersecting the wall 42. The recessed surface 44 is prepared for engagement with the vertical wall 32 on the stem 15, and permits the thickness of the wall 42 to be maintained at one-half the thickness of the stock while assisting in maintaining the center bar normal to the stern.

As seen in FIGURE 6, the stem 15 is aligned with the slot 14 and the tongues 17 and 18 (shown in phantom) positioned with the free ends projecting through the slot 14 beyond the opposite face 46 of the center bar 11. The overall dimension of the tongues 17 and 18 is such that they may be easily positioned in the slot 14. The center bar 11 is aligned with the axis of the stem 15 since the vertical surface 22 engages the face 45 of the center bar 11 at the upper end, while the recessed surface 44 engages the wall 32, as seen in FIG- URE 7. The tongues 17 and 18 are expanded or deformed by a punch, shown fragmentarily at 56 and having a flat end 47 between tapered expander walls 48 and 49. The flat end 47 of the punch 56 enters between the chamfered surfaces 24 and 28 on the tongues 18 and 17, respectively, and expands into the shape gen erally shown in solid lines in FIGURES 6 and 7.

As seen in FIGURE 7, the chamfered ends 28 and 29, and 24 and of the tongues 17 and 18 are deformed along with a portion of the adjacent wall so that the outwardly facing walls of the tongues 17 and 18 overlie the outer surface 46 of a center bar 11, rigidly clamping the opposite face 45 and recessed surface or wall 44 of the center bar to the shoulders 22 and 32, respectively. It can be appreciated that the reduction in the thickness of the wall 42 forming the lower boundary of the slot 14 permits the thickness between the wall 32 and the outer edge to be of the order of about one-half the total thickness of the stem for good rigidity. Since the vertical wall 44 is recessed, making the wall 42 of reduced thickness, the transverse dimension of the stem between the wall 32 and the side margin can be maintained at about onehalf the overall width of the stem, thereby avoiding any lateral weakness which conceivably could result in stem failure by bending or fracture when subjected to stresses encountered in blade clamping.

From a consideration of the foregoing, it can be appreciated that the present center bar and stem assembly is economical to manufacture. Each of these parts may he formed by a conventional stamping technique from soft and easily worked material such as brass. The use of stock material having a polygonal cross-sectional shape for the stem reduces the amount of material required for each razor without adversely affecting the strength, accuracy or functioning. The use of sheet or fiat rod stock and a stamping-coining operation to form the threads results in a more economical stem. The threads receive an operating knob which permits opening and closing of the sectional caps. Assembly is accomplished without any additional parts, such as rivets, but may be achieved by merely deforming the tongues into overlapping engagement with the side of the center bar through a simple punching operation. Location of the center bar relative to the stem is controlled through the location of vertical walls on the stem 15 and co-operating surfaces on the center bar 11.

Upon a consideration of the foregoing, it will become obvious to those skilled in the art that various modifications may be made without departing from the invention embodied herein. Therefore, only such limitations should be imposed as are indiacted by the spirit and scope of the appended claims.

Iclaim:

1. A spider stern and center bar assembly comprising a spider stern of polygonal cross section, thread means formed at one end of said spider stern for receiving an operating knob, tongue means formed at an opposite end of said spider stem, a slot formed centrally of said center bar and having an overall vertical dimension slightly greater than the overall height of said tongue means to permit positioning thereof in said slot, said tongue means being deformed to engage a side wall portion of said slot and thereby join said center bar to said stem.

2. The spider stem and center bar assembly of claim 1 wherein said tongue means includes a pair of axially spaced projections formed on said stem and extending transversely of the axis thereof, said spaced projections being positioned in said slot formed centrally of said center bar and having end portions thereof projecting beyond said center bar, which end portions are deformed to overlie a portion of said center bar.

3. The spider stem and center bar assembly of claim 1 wherein said slot in said center bar is bounded on all sides by wall portions, said wall portion forming the lower boundary of said slot being of lesser depth than adjoining wall portions thereby to form a vertical surface adapted for engagement with a vertical wall portion formed on said stem along the axis thereof and thereby locate said center bar relative to said stem.

4. A spider stem for joining to a center bar to form a spider subassernbly, said spider subassernbly adapted for use in a safety razor of the sectional cap type, said spider stem comprising an elongated rod-like member of polygonal cross section having a threaded end adapted to receive an operating knob, first and second laterally projecting tongues extending from said stem and adapted for insertion into a slot formed in a center bar, each of said tongues being defined by laterally extending upper and lower walls, said first tongue being closest to said threaded end and having the lower wall thereof terminating at a vertical wall disposed along the longitudinal axis of said rod, said upper wall on said second tongue being longer than said lower wall on said first tongue and terminating in a longitudinally extending shoulder which is laterally offset relative to said longitudinal axis and engageable with a part of said center bar to locate the same relative to the axis of said stem.

References (Iited UNITED STATES PATENTS 3,050,852 8/1962 Nissen 3060.5

MYRON C. KRUSE, Primary Examiner. 

